cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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arch_timer.c (12718B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * arch_timer.c - Tests the aarch64 timer IRQ functionality
      4 *
      5 * The test validates both the virtual and physical timer IRQs using
      6 * CVAL and TVAL registers. This consitutes the four stages in the test.
      7 * The guest's main thread configures the timer interrupt for a stage
      8 * and waits for it to fire, with a timeout equal to the timer period.
      9 * It asserts that the timeout doesn't exceed the timer period.
     10 *
     11 * On the other hand, upon receipt of an interrupt, the guest's interrupt
     12 * handler validates the interrupt by checking if the architectural state
     13 * is in compliance with the specifications.
     14 *
     15 * The test provides command-line options to configure the timer's
     16 * period (-p), number of vCPUs (-n), and iterations per stage (-i).
     17 * To stress-test the timer stack even more, an option to migrate the
     18 * vCPUs across pCPUs (-m), at a particular rate, is also provided.
     19 *
     20 * Copyright (c) 2021, Google LLC.
     21 */
     22
     23#define _GNU_SOURCE
     24
     25#include <stdlib.h>
     26#include <pthread.h>
     27#include <linux/kvm.h>
     28#include <linux/sizes.h>
     29#include <linux/bitmap.h>
     30#include <sys/sysinfo.h>
     31
     32#include "kvm_util.h"
     33#include "processor.h"
     34#include "delay.h"
     35#include "arch_timer.h"
     36#include "gic.h"
     37#include "vgic.h"
     38
     39#define NR_VCPUS_DEF			4
     40#define NR_TEST_ITERS_DEF		5
     41#define TIMER_TEST_PERIOD_MS_DEF	10
     42#define TIMER_TEST_ERR_MARGIN_US	100
     43#define TIMER_TEST_MIGRATION_FREQ_MS	2
     44
     45struct test_args {
     46	int nr_vcpus;
     47	int nr_iter;
     48	int timer_period_ms;
     49	int migration_freq_ms;
     50};
     51
     52static struct test_args test_args = {
     53	.nr_vcpus = NR_VCPUS_DEF,
     54	.nr_iter = NR_TEST_ITERS_DEF,
     55	.timer_period_ms = TIMER_TEST_PERIOD_MS_DEF,
     56	.migration_freq_ms = TIMER_TEST_MIGRATION_FREQ_MS,
     57};
     58
     59#define msecs_to_usecs(msec)		((msec) * 1000LL)
     60
     61#define GICD_BASE_GPA			0x8000000ULL
     62#define GICR_BASE_GPA			0x80A0000ULL
     63
     64enum guest_stage {
     65	GUEST_STAGE_VTIMER_CVAL = 1,
     66	GUEST_STAGE_VTIMER_TVAL,
     67	GUEST_STAGE_PTIMER_CVAL,
     68	GUEST_STAGE_PTIMER_TVAL,
     69	GUEST_STAGE_MAX,
     70};
     71
     72/* Shared variables between host and guest */
     73struct test_vcpu_shared_data {
     74	int nr_iter;
     75	enum guest_stage guest_stage;
     76	uint64_t xcnt;
     77};
     78
     79struct test_vcpu {
     80	uint32_t vcpuid;
     81	pthread_t pt_vcpu_run;
     82	struct kvm_vm *vm;
     83};
     84
     85static struct test_vcpu test_vcpu[KVM_MAX_VCPUS];
     86static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS];
     87
     88static int vtimer_irq, ptimer_irq;
     89
     90static unsigned long *vcpu_done_map;
     91static pthread_mutex_t vcpu_done_map_lock;
     92
     93static void
     94guest_configure_timer_action(struct test_vcpu_shared_data *shared_data)
     95{
     96	switch (shared_data->guest_stage) {
     97	case GUEST_STAGE_VTIMER_CVAL:
     98		timer_set_next_cval_ms(VIRTUAL, test_args.timer_period_ms);
     99		shared_data->xcnt = timer_get_cntct(VIRTUAL);
    100		timer_set_ctl(VIRTUAL, CTL_ENABLE);
    101		break;
    102	case GUEST_STAGE_VTIMER_TVAL:
    103		timer_set_next_tval_ms(VIRTUAL, test_args.timer_period_ms);
    104		shared_data->xcnt = timer_get_cntct(VIRTUAL);
    105		timer_set_ctl(VIRTUAL, CTL_ENABLE);
    106		break;
    107	case GUEST_STAGE_PTIMER_CVAL:
    108		timer_set_next_cval_ms(PHYSICAL, test_args.timer_period_ms);
    109		shared_data->xcnt = timer_get_cntct(PHYSICAL);
    110		timer_set_ctl(PHYSICAL, CTL_ENABLE);
    111		break;
    112	case GUEST_STAGE_PTIMER_TVAL:
    113		timer_set_next_tval_ms(PHYSICAL, test_args.timer_period_ms);
    114		shared_data->xcnt = timer_get_cntct(PHYSICAL);
    115		timer_set_ctl(PHYSICAL, CTL_ENABLE);
    116		break;
    117	default:
    118		GUEST_ASSERT(0);
    119	}
    120}
    121
    122static void guest_validate_irq(unsigned int intid,
    123				struct test_vcpu_shared_data *shared_data)
    124{
    125	enum guest_stage stage = shared_data->guest_stage;
    126	uint64_t xcnt = 0, xcnt_diff_us, cval = 0;
    127	unsigned long xctl = 0;
    128	unsigned int timer_irq = 0;
    129
    130	if (stage == GUEST_STAGE_VTIMER_CVAL ||
    131		stage == GUEST_STAGE_VTIMER_TVAL) {
    132		xctl = timer_get_ctl(VIRTUAL);
    133		timer_set_ctl(VIRTUAL, CTL_IMASK);
    134		xcnt = timer_get_cntct(VIRTUAL);
    135		cval = timer_get_cval(VIRTUAL);
    136		timer_irq = vtimer_irq;
    137	} else if (stage == GUEST_STAGE_PTIMER_CVAL ||
    138		stage == GUEST_STAGE_PTIMER_TVAL) {
    139		xctl = timer_get_ctl(PHYSICAL);
    140		timer_set_ctl(PHYSICAL, CTL_IMASK);
    141		xcnt = timer_get_cntct(PHYSICAL);
    142		cval = timer_get_cval(PHYSICAL);
    143		timer_irq = ptimer_irq;
    144	} else {
    145		GUEST_ASSERT(0);
    146	}
    147
    148	xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);
    149
    150	/* Make sure we are dealing with the correct timer IRQ */
    151	GUEST_ASSERT_2(intid == timer_irq, intid, timer_irq);
    152
    153	/* Basic 'timer condition met' check */
    154	GUEST_ASSERT_3(xcnt >= cval, xcnt, cval, xcnt_diff_us);
    155	GUEST_ASSERT_1(xctl & CTL_ISTATUS, xctl);
    156}
    157
    158static void guest_irq_handler(struct ex_regs *regs)
    159{
    160	unsigned int intid = gic_get_and_ack_irq();
    161	uint32_t cpu = guest_get_vcpuid();
    162	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
    163
    164	guest_validate_irq(intid, shared_data);
    165
    166	WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
    167
    168	gic_set_eoi(intid);
    169}
    170
    171static void guest_run_stage(struct test_vcpu_shared_data *shared_data,
    172				enum guest_stage stage)
    173{
    174	uint32_t irq_iter, config_iter;
    175
    176	shared_data->guest_stage = stage;
    177	shared_data->nr_iter = 0;
    178
    179	for (config_iter = 0; config_iter < test_args.nr_iter; config_iter++) {
    180		/* Setup the next interrupt */
    181		guest_configure_timer_action(shared_data);
    182
    183		/* Setup a timeout for the interrupt to arrive */
    184		udelay(msecs_to_usecs(test_args.timer_period_ms) +
    185			TIMER_TEST_ERR_MARGIN_US);
    186
    187		irq_iter = READ_ONCE(shared_data->nr_iter);
    188		GUEST_ASSERT_2(config_iter + 1 == irq_iter,
    189				config_iter + 1, irq_iter);
    190	}
    191}
    192
    193static void guest_code(void)
    194{
    195	uint32_t cpu = guest_get_vcpuid();
    196	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
    197
    198	local_irq_disable();
    199
    200	gic_init(GIC_V3, test_args.nr_vcpus,
    201		(void *)GICD_BASE_GPA, (void *)GICR_BASE_GPA);
    202
    203	timer_set_ctl(VIRTUAL, CTL_IMASK);
    204	timer_set_ctl(PHYSICAL, CTL_IMASK);
    205
    206	gic_irq_enable(vtimer_irq);
    207	gic_irq_enable(ptimer_irq);
    208	local_irq_enable();
    209
    210	guest_run_stage(shared_data, GUEST_STAGE_VTIMER_CVAL);
    211	guest_run_stage(shared_data, GUEST_STAGE_VTIMER_TVAL);
    212	guest_run_stage(shared_data, GUEST_STAGE_PTIMER_CVAL);
    213	guest_run_stage(shared_data, GUEST_STAGE_PTIMER_TVAL);
    214
    215	GUEST_DONE();
    216}
    217
    218static void *test_vcpu_run(void *arg)
    219{
    220	struct ucall uc;
    221	struct test_vcpu *vcpu = arg;
    222	struct kvm_vm *vm = vcpu->vm;
    223	uint32_t vcpuid = vcpu->vcpuid;
    224	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[vcpuid];
    225
    226	vcpu_run(vm, vcpuid);
    227
    228	/* Currently, any exit from guest is an indication of completion */
    229	pthread_mutex_lock(&vcpu_done_map_lock);
    230	set_bit(vcpuid, vcpu_done_map);
    231	pthread_mutex_unlock(&vcpu_done_map_lock);
    232
    233	switch (get_ucall(vm, vcpuid, &uc)) {
    234	case UCALL_SYNC:
    235	case UCALL_DONE:
    236		break;
    237	case UCALL_ABORT:
    238		sync_global_from_guest(vm, *shared_data);
    239		TEST_FAIL("%s at %s:%ld\n\tvalues: %lu, %lu; %lu, vcpu: %u; stage: %u; iter: %u",
    240			(const char *)uc.args[0], __FILE__, uc.args[1],
    241			uc.args[2], uc.args[3], uc.args[4], vcpuid,
    242			shared_data->guest_stage, shared_data->nr_iter);
    243		break;
    244	default:
    245		TEST_FAIL("Unexpected guest exit\n");
    246	}
    247
    248	return NULL;
    249}
    250
    251static uint32_t test_get_pcpu(void)
    252{
    253	uint32_t pcpu;
    254	unsigned int nproc_conf;
    255	cpu_set_t online_cpuset;
    256
    257	nproc_conf = get_nprocs_conf();
    258	sched_getaffinity(0, sizeof(cpu_set_t), &online_cpuset);
    259
    260	/* Randomly find an available pCPU to place a vCPU on */
    261	do {
    262		pcpu = rand() % nproc_conf;
    263	} while (!CPU_ISSET(pcpu, &online_cpuset));
    264
    265	return pcpu;
    266}
    267
    268static int test_migrate_vcpu(struct test_vcpu *vcpu)
    269{
    270	int ret;
    271	cpu_set_t cpuset;
    272	uint32_t new_pcpu = test_get_pcpu();
    273
    274	CPU_ZERO(&cpuset);
    275	CPU_SET(new_pcpu, &cpuset);
    276
    277	pr_debug("Migrating vCPU: %u to pCPU: %u\n", vcpu->vcpuid, new_pcpu);
    278
    279	ret = pthread_setaffinity_np(vcpu->pt_vcpu_run,
    280					sizeof(cpuset), &cpuset);
    281
    282	/* Allow the error where the vCPU thread is already finished */
    283	TEST_ASSERT(ret == 0 || ret == ESRCH,
    284			"Failed to migrate the vCPU:%u to pCPU: %u; ret: %d\n",
    285			vcpu->vcpuid, new_pcpu, ret);
    286
    287	return ret;
    288}
    289
    290static void *test_vcpu_migration(void *arg)
    291{
    292	unsigned int i, n_done;
    293	bool vcpu_done;
    294
    295	do {
    296		usleep(msecs_to_usecs(test_args.migration_freq_ms));
    297
    298		for (n_done = 0, i = 0; i < test_args.nr_vcpus; i++) {
    299			pthread_mutex_lock(&vcpu_done_map_lock);
    300			vcpu_done = test_bit(i, vcpu_done_map);
    301			pthread_mutex_unlock(&vcpu_done_map_lock);
    302
    303			if (vcpu_done) {
    304				n_done++;
    305				continue;
    306			}
    307
    308			test_migrate_vcpu(&test_vcpu[i]);
    309		}
    310	} while (test_args.nr_vcpus != n_done);
    311
    312	return NULL;
    313}
    314
    315static void test_run(struct kvm_vm *vm)
    316{
    317	int i, ret;
    318	pthread_t pt_vcpu_migration;
    319
    320	pthread_mutex_init(&vcpu_done_map_lock, NULL);
    321	vcpu_done_map = bitmap_zalloc(test_args.nr_vcpus);
    322	TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap\n");
    323
    324	for (i = 0; i < test_args.nr_vcpus; i++) {
    325		ret = pthread_create(&test_vcpu[i].pt_vcpu_run, NULL,
    326				test_vcpu_run, &test_vcpu[i]);
    327		TEST_ASSERT(!ret, "Failed to create vCPU-%d pthread\n", i);
    328	}
    329
    330	/* Spawn a thread to control the vCPU migrations */
    331	if (test_args.migration_freq_ms) {
    332		srand(time(NULL));
    333
    334		ret = pthread_create(&pt_vcpu_migration, NULL,
    335					test_vcpu_migration, NULL);
    336		TEST_ASSERT(!ret, "Failed to create the migration pthread\n");
    337	}
    338
    339
    340	for (i = 0; i < test_args.nr_vcpus; i++)
    341		pthread_join(test_vcpu[i].pt_vcpu_run, NULL);
    342
    343	if (test_args.migration_freq_ms)
    344		pthread_join(pt_vcpu_migration, NULL);
    345
    346	bitmap_free(vcpu_done_map);
    347}
    348
    349static void test_init_timer_irq(struct kvm_vm *vm)
    350{
    351	/* Timer initid should be same for all the vCPUs, so query only vCPU-0 */
    352	int vcpu0_fd = vcpu_get_fd(vm, 0);
    353
    354	kvm_device_access(vcpu0_fd, KVM_ARM_VCPU_TIMER_CTRL,
    355			KVM_ARM_VCPU_TIMER_IRQ_PTIMER, &ptimer_irq, false);
    356	kvm_device_access(vcpu0_fd, KVM_ARM_VCPU_TIMER_CTRL,
    357			KVM_ARM_VCPU_TIMER_IRQ_VTIMER, &vtimer_irq, false);
    358
    359	sync_global_to_guest(vm, ptimer_irq);
    360	sync_global_to_guest(vm, vtimer_irq);
    361
    362	pr_debug("ptimer_irq: %d; vtimer_irq: %d\n", ptimer_irq, vtimer_irq);
    363}
    364
    365static int gic_fd;
    366
    367static struct kvm_vm *test_vm_create(void)
    368{
    369	struct kvm_vm *vm;
    370	unsigned int i;
    371	int nr_vcpus = test_args.nr_vcpus;
    372
    373	vm = vm_create_default_with_vcpus(nr_vcpus, 0, 0, guest_code, NULL);
    374
    375	vm_init_descriptor_tables(vm);
    376	vm_install_exception_handler(vm, VECTOR_IRQ_CURRENT, guest_irq_handler);
    377
    378	for (i = 0; i < nr_vcpus; i++) {
    379		vcpu_init_descriptor_tables(vm, i);
    380
    381		test_vcpu[i].vcpuid = i;
    382		test_vcpu[i].vm = vm;
    383	}
    384
    385	ucall_init(vm, NULL);
    386	test_init_timer_irq(vm);
    387	gic_fd = vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
    388	if (gic_fd < 0) {
    389		print_skip("Failed to create vgic-v3");
    390		exit(KSFT_SKIP);
    391	}
    392
    393	/* Make all the test's cmdline args visible to the guest */
    394	sync_global_to_guest(vm, test_args);
    395
    396	return vm;
    397}
    398
    399static void test_vm_cleanup(struct kvm_vm *vm)
    400{
    401	close(gic_fd);
    402	kvm_vm_free(vm);
    403}
    404
    405static void test_print_help(char *name)
    406{
    407	pr_info("Usage: %s [-h] [-n nr_vcpus] [-i iterations] [-p timer_period_ms]\n",
    408		name);
    409	pr_info("\t-n: Number of vCPUs to configure (default: %u; max: %u)\n",
    410		NR_VCPUS_DEF, KVM_MAX_VCPUS);
    411	pr_info("\t-i: Number of iterations per stage (default: %u)\n",
    412		NR_TEST_ITERS_DEF);
    413	pr_info("\t-p: Periodicity (in ms) of the guest timer (default: %u)\n",
    414		TIMER_TEST_PERIOD_MS_DEF);
    415	pr_info("\t-m: Frequency (in ms) of vCPUs to migrate to different pCPU. 0 to turn off (default: %u)\n",
    416		TIMER_TEST_MIGRATION_FREQ_MS);
    417	pr_info("\t-h: print this help screen\n");
    418}
    419
    420static bool parse_args(int argc, char *argv[])
    421{
    422	int opt;
    423
    424	while ((opt = getopt(argc, argv, "hn:i:p:m:")) != -1) {
    425		switch (opt) {
    426		case 'n':
    427			test_args.nr_vcpus = atoi(optarg);
    428			if (test_args.nr_vcpus <= 0) {
    429				pr_info("Positive value needed for -n\n");
    430				goto err;
    431			} else if (test_args.nr_vcpus > KVM_MAX_VCPUS) {
    432				pr_info("Max allowed vCPUs: %u\n",
    433					KVM_MAX_VCPUS);
    434				goto err;
    435			}
    436			break;
    437		case 'i':
    438			test_args.nr_iter = atoi(optarg);
    439			if (test_args.nr_iter <= 0) {
    440				pr_info("Positive value needed for -i\n");
    441				goto err;
    442			}
    443			break;
    444		case 'p':
    445			test_args.timer_period_ms = atoi(optarg);
    446			if (test_args.timer_period_ms <= 0) {
    447				pr_info("Positive value needed for -p\n");
    448				goto err;
    449			}
    450			break;
    451		case 'm':
    452			test_args.migration_freq_ms = atoi(optarg);
    453			if (test_args.migration_freq_ms < 0) {
    454				pr_info("0 or positive value needed for -m\n");
    455				goto err;
    456			}
    457			break;
    458		case 'h':
    459		default:
    460			goto err;
    461		}
    462	}
    463
    464	return true;
    465
    466err:
    467	test_print_help(argv[0]);
    468	return false;
    469}
    470
    471int main(int argc, char *argv[])
    472{
    473	struct kvm_vm *vm;
    474
    475	/* Tell stdout not to buffer its content */
    476	setbuf(stdout, NULL);
    477
    478	if (!parse_args(argc, argv))
    479		exit(KSFT_SKIP);
    480
    481	if (test_args.migration_freq_ms && get_nprocs() < 2) {
    482		print_skip("At least two physical CPUs needed for vCPU migration");
    483		exit(KSFT_SKIP);
    484	}
    485
    486	vm = test_vm_create();
    487	test_run(vm);
    488	test_vm_cleanup(vm);
    489
    490	return 0;
    491}